Two spectators entered the armed man, including one using a shopping cart as a weapon.

The witness then took a rubber band to the ground to help the besieged officers.

He said that scared spectators scream, "shoot him, shoot him".

Did you see what happened? E-MAIL: news@heraldsun.com.au

WITCHES HONOR BANGS, SAW MAN IN BLOOD

Witness Christian, who was in a nearby bookstore, said he heard a loud noise and saw the police chasing a man.

"I heard a loud bang, I ran outside and saw everyone was running in the other direction," he said.

"I saw a man covered in blood and saw officers pursuing someone."

Witness Piper said that she and her partner "were about 20 meters from the blast. We saw a guard with blood and a man on the ground (he looked dead), we felt the heat and were very shocked that we did not know how to react? We left immediately and did not know what could happen next. I will most likely not return to the city … "

Businesses are closed near the incident, and the police are calling on people to stay inside.

The Neapoli Café on Russell Place has closed. The staff stayed there and waited for further instructions from the police.

Sam from the cafe said, "There was just a lot of pony. There are only staff here, the police told us to stay. "

Another nearby person said that there had been four loud explosions possibly related to a flaming ute.

Did you see what happened? E-MAIL: news@heraldsun.com.au

Some fled the area, fearing that further explosions might occur.

A spectator in Bourke St said the people were running when the car went up in flames.

"On Bourke Street, a man was stabbed and there was an explosion of a car," he said.

"It was near JB Hi Fi, near the corner of Russell Place."

The viewer said other people were safe.

"They ran into a café and locked themselves in a kitchen," he said.

Another witness who did not want his name to be published said he had set fire to a car in front of the JB Hi-Fi and a man who seemed to be swinging a big knife.

The witness said the police pulled the gun but could not say if the man had been shot or if it had been a "blast" from the car's fire.

"I saw him drop when the police pulled weapons," he said.

"He was down."

The witness said that Herald Sun Two or three policemen stood over the man, who was then dragged into a side street.

He said there was a person who was covered in blood, near the car and received first aid.

The witness said that the injured person was either given a resuscitation or had a possible sore throat.

Michael, from the Treasure Star Karaoke Bar on Bourke Street, said he heard loud noises just before 5pm.

"We just heard the explosion and closed the shop," he said.

"There was a gun noise, there were one or two shots."

SEND POLICE EMERGENCY NOTES

The police used the emergency alert service and sent a message saying, "The police in Victoria are responding to an incident on the corner of Bourke and Swanston streets. Avoid the area. "

The terrorist system of public service was also activated.

The sirens sounded before 6 pm and urged anyone who had information about the incident to contact the police.

Myer has canceled the opening of his Christmas window.

media cameraPolice protection in front of Bourke St. Image: Aneeka Simonismedia cameraSpectators near the corner of the streets Swanston and Bourke. Image: Josh Fagan

A police statement said, "The police are currently in Bourke Street in the CBD. The police initially responded to a report of a burning car near the corner of Swanston Street at 4:20 pm. A man was arrested at the scene and sent to a hospital under critical condition. At this early stage, the police are no longer looking for anyone. A small number of people are being treated for stab wounds.

"The exact circumstances must still be determined at this time.

"The area has been closed off and the public is asked to avoid the area.

"Anyone with information or witness to the incident will be asked to go to the Melbourne West Police Station to make a statement.